The Linear Tape File System (LTFS) format has been put to practical use as a mechanism for accessing data in tape drives as files in a file system. In the LTFS format, metadata such as where data areas constituting a file are located on a tape is associated in the form of an index to realize a file system.
Due to the nature of tape, the LTFS format is used when a file is edited as a mechanism for appending edited data instead of overwriting the previously written data. While this allows a previously written generation of file to be restored, it also takes time to read an edited file.
A similar problem occurs when the data configuration on a tape is backed up to another tape, and the backed up data (files) is read. The time required to read one of the edited files can be reduced by copying only the most recent generation of edited files to another tape, but this so-called logical copy does not allow previously written generations of the file to be restored.